The strongest reasons are **preventing tipping and keeping the countertop’s supports fixed in position**.

- **An open drawer changes the balance.** A loaded drawer puts weight ahead of the cabinet; someone leaning on it or a child climbing it adds more overturning force. Wall screws resist that force. How significant this is depends on the cabinet’s weight, depth, and connections to adjacent units. [IKEA explicitly requires its base cabinets to be secured to the wall for safety.](https://www.ikea.com/ca/en/customer-service/knowledge/articles/6254dcg1-716f-4e87-99f3-c7f5468dfd73.html)
- **A continuous countertop needs stable support.** Cabinets are leveled and often shimmed individually, then fastened together and to the wall. Moving one can disturb that support, stress countertop joints, or cause cracking around cutouts in brittle tops. [Cambria requires supporting cabinets to be structurally sound, straight, level, and square.](https://www.cambriausa.com/quartz-countertops/faq/installation)
- **Anchoring preserves the installation’s alignment.** Repeated drawer pulls, bumps, and leaning against the counter can move a loose unit. Screws keep appliance gaps, cabinet fronts, and wall joints where they were set.

Your cleaning, painting, and flooring advantages are real **for independently movable units with their own tops**. A conventional cabinet run usually has a shared countertop and cabinet-to-cabinet fasteners, so removing the wall screws alone won’t make one cabinet movable. A sink unit also needs its plumbing disconnected before substantial movement; generous access holes only provide clearance around the pipes.

Freestanding kitchen furniture can work when designed for that use. For ordinary fitted cabinets, a few removable screws provide dependable restraint at little installation cost. Plumbing clearance and caulk are secondary reasons.